|
| |
|
|
A050929
|
|
Number of directed multigraphs with loops on 4 nodes with n arcs.
|
|
4
| |
|
|
1, 2, 11, 47, 198, 713, 2423, 7388, 21003, 55433, 137944, 324659, 729022, 1567139, 3242954, 6479759, 12547894, 23607614, 43267994, 77405064, 135435666, 232137202, 390371944, 644897542, 1047890293, 1676518363, 2643628813
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
FORMULA
| G.f.: (x^26-x^25 + 4*x^24 + 18*x^23 + 63*x^22 + 151*x^21 + 402*x^20 + 790*x^19 + 1511*x^18 + 2353*x^17 + 3400*x^16 + 4296*x^15 + 5115*x^14 + 5266*x^13 + 5115*x^12 + 4296*x^11 + 3400*x^10 + 2353*x^9 + 1511*x^8 + 790*x^7 + 402*x^6 + 151*x^5 + 63*x^4 + 18*x^3 + 4*x^2-x + 1)/((x^4-1)^4*(x^3-1)^5*(x^2-1)^4*(x-1)^3).
|
|
|
CROSSREFS
| Cf. A005993.
Sequence in context: A089682 A198693 A178710 * A019005 A112288 A192699
Adjacent sequences: A050926 A050927 A050928 * A050930 A050931 A050932
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 30 1999
|
| |
|
|
